Flexo-photovoltaic effect

• DOI: 10.1126/science.aan3256
• Publication Date: 2018-04-19T18:05:48Z
• Authors: Ming-Min Yang; Dong Jik Kim; Marin Alexe
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy; QC

It is highly desirable to discover photovoltaic mechanisms that enable enhanced efficiency of solar cells. Here we report the bulk effect, which free from thermodynamic Shockley-Queisser limit but usually manifested only in noncentrosymmetric (piezoelectric or ferroelectric) materials, can be realized any semiconductor, including silicon, by mediation flexoelectric effect. We used either an atomic force microscope a micrometer-scale indentation system introduce strain gradients, thus creating very large currents centrosymmetric single crystals strontium titanate, titanium dioxide, and silicon. This gradient-induced call flexo-photovoltaic functions absence p-n junction. finding may extend present cell technologies boosting energy conversion wide pool established semiconductors.